Yup, replaced a top end on a 2000 KX125 this winter and used one of those kits. The rider (a good friend of mine) noticed it wasnt starting well, and all that good stuff. Well, at his first race (southwick, NESC) I went to start both of our bikes, and warm them up a little before practice. My dad and him are watching me, and notice coolant blowing out the base gasket. We rip the top end, and there is coolant everywhere... it seems that regular gaskets have a metal layer, and to acheive high compression these gaskets just skip that stage... this resulted in a blown base gasket weeks after installation... pretty much, to sum that up, dont buy them! You will most likely regret it.